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Hi,

Recently I test drove a 1994 Isuzu MU 3.1L Turbo Diesel. It is in tidy condition for 250,000kms, no smoke and it drove well. I'm concerned abour a noise that it makes under acceleration, I know you can normally hear the turbo but this really was quite loud, sort of like a squealing belt crossed with a turbo. I tried revving the engine out of gear and it did sound like a belt was making a bit of noise. In gear the noise only occurred while accelerating, the sound stopped when coasting or engine braking.

What do you think?
Cheers

There are any number of possibilities - (eg; belt, transmission, turbo, air leak, water pump, a noisy bearing of some sort etc, etc), and not possible to determine without hearing it. If you think it sounds like a belt squeal, you can try spraying some water on the belt to see if the noise disappears. However, I think it would pay for you to have a mechanic check the vehicle over, and give you an opinion on the noise and the vehicle in general.